I marked interview as Difficult, not because tasks are difficult, but because of - testing environment is not convenient. Second task is 4 intermediate level SQL questions. First task is actually task for DFS algorithm, but main problem - it not pure algorithm, this is problem surrounded with ASPX staff(for .Net developers). So if did not have experience with ASPX for a long time, it will take longer to resolve it. And the last task depends on first task, so if there is no 1st task solution, there is no 3rd tak solution.